For latest vbulletin threads on wordpress homepage, I found this wordpress widget much easier to use and much more reliable.
Simple RSS Feeds Widget
Plugin link at wordpress:
http://wordpress.org/extend/plugins/...-feeds-widget/
Author homepage:
http://petitnuage.fr/developpement/s...get-wordpress/
use the RSS feed link of your forums and put that into the wordpress widget after install.
use example
http://www.yoursite.com/forum/external.php?type=rss2